1. What is the name of the iOS framework which provides crucial infrastructure and UI components for implementing graphical, event-driven apps? Circle one answer.

a. Foundation

b. AppKit

c. UIKit

d. CoreData

2. Which is the best definition of an Optional in Swift?

a. Another way to say an instance is currently nil

b. A form of error handling

c. They tell you that a value is always going to be present

d. A type-safe way to represent the possible absence of a value